Post-operative pelvic radiation therapy is the current standard of care for many patients with cervical cancer, yet may affect surrounding organs and tissue and be associated with long-term gastrointestinal side effects. IG-IMRT uses technology to manipulate beams of radiation to conform to the shape of a tumor, thus allowing clinicians to limit exposure to surrounding tissue.

The phase III randomized clinical trial, conducted at Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre in Mumbai, India, included 240 patients, ages 18 and over who were undergoing adjuvant chemoradiation therapy (combined chemotherapy and radiation therapy) and had no pre-existing bowel disease or injury. This planned interim analysis of the study assessed 117 of the patients who had completed an average of 20-months follow-up (range: two to 46 months). Patients were categorized into two groups: 56 patients received 3-D CRT and 61 patients received IG-IMRT. Patient groups were randomized and had similar treatment histories, with 41.3 percent (23 patients) of the 3-D CRT group having radical hysterectomies and 43.5 percent (27 patients) of the IG-IMRT group having radical hysterectomies. Additionally, 91.8 percent (51 patients) of the 3-D CRT group had chemoradiation therapy, with 85.5 percent (52 patients) of the IG-IMRT group undergoing chemoradiation therapy. RT included 50 Gy, administered over 25 treatments in a five-week timeframe. CRT patients received Cisplatin (40 mg/m2) congruently. This was followed by two fractions of brachytherapy (cylinder based intravaginal brachytherapy) of 6 Gy each.

Patients randomized to the 3-D CRT group received treatment on a linear accelerator, and the IG-IMRT patients received treatment using Tomotherapy. Strict constraints were applied in the administration of the IG-IMRT to ensure that no more than 200 cc and 100 cc of small bowel received 15 and 40 Gy respectively.

At each follow-up visit, patients' bowel side effects were recorded by clinicians using 11 symptom scales of Common Toxicity Criteria for Adverse Events (CTCAE version 3.0). In the 3-D CRT group, 58.9 percent (33 patients) experienced ≥2 acute bowel toxicity (indicating moderate to severe diarrhea, vomiting, nausea, lower abdominal distension or pain) compared to 54 percent (33 patients) in the IG-IMRT group (p=0.59). The reported late grade ≥2 bowel toxicity was 25 percent (14 patients) in the 3-D CRT group and 11.4 percent (7 patients) in the IG-IMRT group (p=0.13); and the late grade ≥3 bowel toxicity (indicating severe diarrhea, lower abdominal pain, subacute intestinal obstruction requiring medical or surgical intervention, bowel perforation or death) was 17.6 percent (10 patients) in the 3-D CRT group and 3.2 percent (2 patients) in the IG-IMRT group (p=0.02). Further, research indicated that neither the surgery type nor the administration of CRT had an impact on bowel side effects.

"These initial results of this interim analysis are encouraging and trend toward possibly a clinically important reduction in moderate-to-severe bowel side effects with the use of IG-IMRT, however at interim analysis the results are statistically nonsignificant," said Supriya Chopra, MD, lead study author and associate professor of radiation oncology at ACTREC, Tata Memorial Centre in Mumbai, India. "While we evaluated patients with cervical cancer in this trial, a significant proportion of patients with other cancers undergo postoperative pelvic radiation worldwide. Therefore, the results of this trial could impact the choice of future radiation delivery technique for various pelvic malignancies."

The abstract, "Phase III RCT of Postoperative Adjuvant Conventional Radiation (3DCRT) Versus IGIMRT for Reducing Late Bowel Toxicity in Cervical Cancer (PARCER) (NCT01279135/CTRI2012/120349): Results of Interim Analyses" will be presented in detail at the Plenary Session at ASTRO's 57th Annual Meeting at 2:15 p.m. Central time on Monday, October 19, 2015.

To speak with Dr. Chopra, please call Nancy Mayes from October 18-21, 2015 in the ASTRO Press Office at the Henry B. González Convention Center, San Antonio, at 210-258-8104 or 210-258-8105, or email press@astro.org.

ASTRO's 57th Annual Meeting, being held at the Henry B. González Convention Center in San Antonio, October 18-21, 2015, is the nation's premier scientific meeting in radiation oncology. The 2015 Annual Meeting is expected to attract more than 11,000 attendees including oncologists from all disciplines, medical physicists, dosimetrists, radiation therapists, radiation oncology nurses and nurse practitioners, biologists, physician assistants, practice administrators, industry representatives and other health care professionals from around the world. Led by ASTRO President Bruce D. Minsky, MD, FASTRO, a radiation oncologist specializing in gastrointestinal cancers, Professor of Radiation Oncology, and the Frank T. McGraw Memorial Chair at The University of Texas MD Anderson Cancer Center, Houston, the theme of the 2015 Meeting is "Technology Meets Patient Care." Dr. Minsky's Presidential Symposium, "Multidisciplinary Management of Esophageal and Rectal Cancers," will feature Leonard L. Gunderson, MD, MS, FASTRO, and Joel E. Tepper, MD, FASTRO, to highlight imaging, staging, genomics and data mining approaches, as well as the latest advances in esophageal and colorectal cancer treatment. ASTRO's four-day scientific meeting includes presentation of more than 2,100 abstracts: five plenary papers, 351 oral presentations, 1,609 posters and 171 digital posters in more than 53 educational sessions and 26 scientific panels for 20 disease-site tracks. Three keynote speakers will address a range of topics including cancer biology in radiation oncology, the essential roles of a physician, and patient safety: Arul Chinnaiyan, MD, PhD, Professor and Director, Michigan Center for Translational Pathology; Francisco G. Cigarroa, MD, Past President and Chancellor, University of Texas; and Gerald B. Hickson, MD, Senior Vice President and Assistant Vice Chancellor, Vanderbilt University Medical Center.

ABOUT ASTRO

ASTRO is the premier radiation oncology society in the world, with nearly 11,000 members who are physicians, nurses, biologists, physicists, radiation therapists, dosimetrists and other health care professionals that specialize in treating patients with radiation therapies. As the leading organization in radiation oncology, the Society is dedicated to improving patient care through professional education and training, support for clinical practice and health policy standards, advancement of science and research, and advocacy. ASTRO publishes three medical journals, International Journal of Radiation Oncology • Biology • Physics (www.redjournal.org), Practical Radiation Oncology (www.practicalradonc.org) and Advances in Radiation Oncology (www.advancesradonc.org); developed and maintains an extensive patient website, www.rtanswers.org; and created the Radiation Oncology Institute (www.roinstitute.org), a non-profit foundation to support research and education efforts around the world that enhance and confirm the critical role of radiation therapy in improving cancer treatment. To learn more about ASTRO, visit www.astro.org.